MDM2 and cancer: For example, many RING finger E3s, including the anaphase promoting complex (APC), MDM2 proto-oncogene (MDM2), breast cancer associated gene 1 (BRCA1), calcineurin B-like proteins (CBLs), and von Hippel-Lindau tumor suppressor (VHL), have been demonstrated to be implicated in either the suppression or the progression of cancer [25, 26].